Signaling system for railroads



June 2, 1936.

E. B. KEMPSTE'R. JR

SIGNALING SYSTEM FOR'RAILROADS l Filed May 4, 1932 Patented June 2, 1936 UNITED STATES .SIGNALING SYSTEM FOR RAILROADS Ernest B. Kempster, Jr., Rochester, N. Y., as-

signor to General Railway Signal Company,

Rochester, N. Y.

Application May 4, 1932, Serial No. 609,186

8 Claims.

This invention relates to a signaling system for railroads of the absolute-permissive-block type, and more particularly to the provision of means for safe-guarding traflic in spite of the open condition of a track switch of an intermediate spur track, and also upon the entrance of a train into the single track section from such spur track.

In a railway signaling system of the absolutepermissive-block, or A. P. B. type, such for instance, as shown in the prior patent to S. N. Wight No. 1,294,736, granted February 18, 1919, stick relays are used to set up traflc in accordance with the direction in which a train is moving, the organization being such that traic is absolutely blocked from moving in the opposite direction, and a stick relay at each signal is picked up by the passage of a train in the. proper direction, and this stick relay permits the next signal in the rear to indicate caution when the block just ahead of such stick relay is occupied. For example, in said patent, the pole changing of signal control relay, such as 58, removes plus energy from the signal cl-ear Wire and leaves it only on the signal caution wire whereby to cause the signal to go to caution, as is well understood in this art. In accordance with present invention it is proposed to so interlock the two stick relays at the two signals approaching the spur track, or turn out, that both of these stick relays may be controlled through the same line circuit, thereby economizing in line wire, and it is further proposed to include in this line circuit a switch box contact operated by the track switch of such spur track, so that the two mentioned stick relays will b-e deenergized when the track switch is Opened, and once deenergized they, or either of them, cannot be picked up except by the passage of a train in the proper direction, providing of course, that the track switch has in the meantime been placed back into its normal main track position.

Other objects, purposes and characteristic features of the invention will in part be pointed out hereinafter, and will in part be obvious from the accompanying drawing.

In describing the invention in detail reference Will be made to the accompanying drawing, in

which:-

Fig. l shows conventionally one form present invention; and

Fig. 2 shows the split battery employed at each signal location having its midpoint connected to a common return wire C.

Referring to the drawing, the system shown of the therein is a typical A. P. B system similar to the one illustrated in the Wight patent above mentioned, and in certain respects resembling the system shown in the application of. Mersereau and Wells, Ser. No. 511,046 led January 24, 1931, f' now Patent No. 1,878,083, granted September 20, 1932.

In Fig. 1 of the drawing the track rails 5 of the main track have been shown divided into blocks by insulating joints 6, each block of which includes a center-fed track circuit including the track battery "I and the track relays T (having a suitable exponent). of which the track relays T1, T2, T3 and T4 only have been illustrated. At the entrance of each block, for each direction of traic there is provided a wayside signal, which for convenience has been illustrated as a semaphore signal, and of which the signals 2 and 4 have been illustrated for east-bound traic, and the signals I and 3 have been illustrated for west-bound traic. Each of these signals is controlled by its associated home relay I-ID having a preiix corresponding to the number of the signal, and each home relay is controlled in accordance with the track relays in the block next in advance, the pole changer relay PC (having a proper prefix) in advance and the stick relay S (having a proper prefix) in advance. At an'intermediate point in the block shown, there is a spur track, or diverging route, including track rails 8 and including a track switch 9, and this track switch has point detector contacts associated therewith, including contacts Il), II and 3S associated respectively with the signals 2 and 3.

Under normal clear trafc conditions all of the four signals I, 2, 3 and I assume the clear position, under which condition the relay 2HD is energized through the following circuit:-be ginning at the terminal (-5-) of a suitable battery, such as the battery B shown in Fig. 2, front contact I5 of the pole changer relay 4PC, wire I 6, front contact I1 of the track relay T3, wire I8, switch box contact II, wire I9, front contact 2K! of the track relay T2, wire 2l, winding of the home relay 2I-ID, to the common return wire C connected to the midpoint of said battery. Sim.- ilarly, the home relay 3I-ID is energized through the following circuit-beginning at the terminal (-I) of a suitable battery, front contact 25 vrof the relay IPC, wire 26, front contact 21 of track relay T2, wire 28, switch box contact Ill, Wire 29, front contact 30 of the track relay T3, wire 3|, Winding of the relay 3HD, to the common return wire C connected to the midpoint of said battery.

The pole changer relays, such as IPC, 2PC, 3PC and 4PC are merely slow acting neutral repeater relays for the respective home relays having the same prefix, these relays being respectively controlled through the contacts 33, 34, 35, and 36 of their respective associated horne relays. These relays have been termed pole changer or PC relays, because the contacts of each of these relays determines whether the home relay of the next signal in the rear shall be energized by current of positive or negative polarity. The directional stick relays IS and 4S are controlled in the usual manner, for instance, as shown in the application of Mersereau and Wells, and these control circuits are for convenience omitted. It is believed that the purpose and function of the stick relays 2S and 3S and their control circuits are most clearly understood by considering theV operation of thev system.

Operation As illustrated, the stick relays 2S and 3S are normally deenergized. Let us assume that there is an east-bound train approaching the signal 2 in thedirection governed by this signal. The presence of thisV approaching train, for reasons well understood by those skilled in the signaling art, causes deenergization of the home relay I HD which results in deenergization of the relay IPC, which in turn deenergizes the home relay 3HD next in the rear, and drops contact 35 of relay 3HD, resulting in deenergization of the relay 3PC. The dropping of the relays 3HD and 3PC, places the stick relay 2S' in condition for picking up, and this relay 2S will pick up as soon as the east-bound train passes the signal 2.

Let us now assume that the east-bound train passes the signal 2, resulting in the dropping of the track relay T2, due to the shunting action of the car wheels on the track circuit containing this track relay T2, thereby closing the following energizing circuit for the stick relay 2S, as a result of the closure of the back contact 56 of the track relay T22- beginning at the terminal (-1-) of a suitable battery, back contact 40 of the stick relay 3S, wire 4 I, back contact 42 of the relay 3PC, wires 43 and 44, switch box or point detector contact I2, wires 54 and 53, front contact 52 of the relay 2PC, Wire 55, back contact 56 of the track relay T2, wires 51 and 5B, winding of the relay 2S, to the common return wire C. The closure of this pick-up circuit for the relay 2S causes this relay 2S to be energized and close its front contacts, as a result of which the following stick circuit is closed, it being understood that dropping of the track relay T2 results in dropping of the home relay 2HD, which in turn after the expiration of a short period of time, since the relay 2PC is slow acting, causes the relay 2PC to assume its deenergized positionz-beginning at the terminal (-1-), back contact 40 of the stick relay 3S, wire 4I, back contact 42 of the relay SPC, wires 43 and 44, point detector contact I2, wires 54 and 66, back contact 6I of the relay 2HD, wire 62, front stick contact 63 of the stick relay 2S, wires 64, 65 and 58, winding of the stick relay 2S, to the common return wire C. There is also an auxiliary stick circuit, which is the same as the stick circuit just traced up to and including the wire 54. and from whence it continues through wire 53,

back contact 52 of the relay 2PC, Wire 5I, another stick contact 56 of the stick relay 2S, wires 66, 65 and 58, winding of the stick relay 2S to the common return wire C. The picking up of the stick relay 2S, through the medium of its front contact 61 and back contact 68 of the relay 2PC causes current of negative polarity to be applied to the next HD relay (not shown) in the rear.

Let us now assume that the east-bound train in question, now moving from the signal 2 to the signal 4, advances to a point beyond the signal 4, as a result of which the stick relay 4S is picked up in any suitable and usual manner, as understood by those skilled in the art of A. P. B. signaling. The picking up of the stick relay 4S and the dropping of the pole changer relay 4PC in response to the passage of the train by the signal| 4, causes the relay ZHD to be energized by current of negative polarity, as a result of which one of the stick circuits for the stick relay 2S is broken at the back contact 6I of the relay 2HD, and the other stick circuit for the relay 2S is broken at the back contact 52 of the relay 2PC, so that the relay 2S is again deenergized. Also, shifting of the polar armature of relay 2HD for example takes plus energy oil. of the signal clear control wire, to leave it on the signal caution control wire only, to thus put the signal 2 to caution.

In the same way as just explained a west-bound train approaching the signal 3 will result in the deenergization of the home relay 4HD, which in turn will result in the deenergization of relay ZHD. Let us now assume that this west-bound train passes the signal 3 under which condition the stick relay 3S will be picked up through the following pick-up circuitz-beginning at the terminal of a suitable split battery, back contact 50 of the stick relay 2S, wire 5I, back contact 52 of the relay 2PC, wires 53 and 54, switch box contact I2, wires 44 and 43, front contact 42 of the relay 3PC, wire 45, back contact 45 of thev track relay T3, wires 41 and 48, winding of the stick relay 3S to the common return wire C. With the relay 3S once picked up, it will be stuck up through the following two stick circuits as soon as the relays 3HD and 3PC assume their de-energized position:-(1) beginning at the terminal (-1-), back contact 5I] of the stick relay 2S, wire 5I, back contact 52 of the relay 2PC, wires 53 and 54, contact I2, Wires 44 and 10, back contact 1l of the relay 3HD, wire 12, stick contact 13 of the relay 3S, wires 14 and 48, winding of the relay 3S to the common return wire C; and (2) the same stick circuit up to and including the wire 44, wire 43, back contact 42 of the relay BPC, wire 4 l, front stick contact 40 of the relay 3S, wires 16 and 48, winding of the relay 3S to the common return wire C. As soon as the west-bound train under consideration passes the signal I next in advance. this relay 3HD will be energized by current of negative polarity, for reasons already explained, thereby resulting in the energization of the relay BPC, and the opening of the two stick circuits just traced at the back contact 1I of the relay 3HD and the back contact 42 of the relay BPC.

It will be observed that the functioning of the system as thus far described is similar to the functioning of the usual absolute-permissiveblock system, but that the structure is different in that the pick-up and stick circuits Vof the two stick relays 2S and 3S include the saine line wires 44-54, and include the same point detector contacts I2. The purpose of this departure from earlier systems results in the advantage of eliminating one line wire, in that both of the stick relays 2S and 3S employ the same line wire, and at the same time the arrangement affords an interlock between the relays 2S yand 3S that would otherwise not be present. This interlock exists because the relay 2S must be picked up through the back contact of the relay 3S and the relay 3S must be picked up through the back contact of the relay 2S. Also, the same point detector contact I2 serves to deenergize both of these stick relays 2S and 3S upon opening of the track switch 9. In other words, irrespective of whether the relay 2S, or whether the relay 3S is energized opening of the track switch 9 will deenergize such energized stick relay. If a stick relay has been thus deenergized by the opening of a track switch 9, such stick relay cannot again be picked up except by' the passage of a train, so that irrespective of whether the train is coming from, or entering into the spur track 8, moves in an easterly direction or in a westerly direction, all of the signals governing traffic toward the spur track 8 will be put to stop, and the direction of travel is es tablished by the train itself as it passes either the signal I or the signal 4.

Having thus shown and described only one particular embodiment of the present invention, it is desired to be understood that the particular system conventionally illustrating this invention has not been selected for the purpose of showing the exact construction preferably employed in practicing the invention nor has it been selected to illustrate the scope of the invention, but it has been merely selected to facilitate description of the underlying principles of the invention and one way of carrying out these principles, and it is further desired to be understood that additions, modifications and alterations may be made to adapt the invention to the particular problem encountered in practicing the same, all without departing from the spirit or scope of the invention except as demanded by the scope of the following claims.

What I claim as new is:-

l. In a single track signaling system of the absolute-permissive-block type, the combination with two signals for governing traflic in opposite directions, of a pole changing stick relay associated with each of said signals for when energized pole changing a control circuit for causing the next signal in the rear to indicate caution, and of a pick-up and a stick circuit for each of said stick relays including a back contact of the other of said stick relays.

2. In a single track signaling system of the absolute-permissive-block type, the combination with two signals for governing traic in opposite directions, a stick relay associated with each of said signals for when energized causing the next signal in the rear, and governing traffic in the same direction, to indicate caution, a line wire extending from one of said two signals to the other, and a stick circuit for each of said stick relays including said line wire.

3. In a single track signaling system of the absolute-permissive-block type, the combination with two signals for governing traffic in opposite directions, a stick relay associated with each of said signals for when energized causing the next signal in the rear to indicate caution, a line wire extending from one of said two signals to the other, and a pick-up and a stick circuit for each of said stick relays including said line wire.

4. In a single track signaling system of the absolute-permissive-block type, in combination, with two signals for governing traic in opposite directions, a stick relay associated with each of said signals, which stick relay, when energized, causes the next signal in the rear to indicate caution, aline wire extending from one of said two signals to the other, a stick circuit for each .of said stick relays including said line wire, a

track switch located between said signals, and a contact in said line wire closed only if said track switch assumes the main track position.

5. In a single track signaling system of the absolute-permissive-block type, in combination, with two signals for governing tra'ic in opposite directions, a stick relay associated with each of said signals, which stick relay, when energized, causes the next signal in the rear to indicate caution, a line wire extending from one of said signals to the other of said signals, a pick-up circuit for each of said stick relays including said line wire, a track switch located between said signals, and a contact in said line wire closed only if said track switch assumes the main track position.

6. In a single track signaling system of the absolute-permissive-block type, in combination, with two signals for governing tramo in opposite directions, a stick relay associated with each of said signals for, when energized, causing the next signal in the rear to indicate caution, a line wire extending from one of said signals to the other of said signals, a pick-up and a stick circuit for each of said stick relays including said line wire, a track switch located between said signals, and a contact in said line wire closed only if said track switch assumes the main track position.

7. In a single track signaling system of the absolute-permissive-block type, in combination, with two signals for governing trani-c in opposite directions, a stick relay associated with each of said signals, which stick relay, when energized, causes the next signal in the rear to indicate caution, a line wire extending'from one of said signals to the other of said signals, a stick circuit for each of said stick relays including said line wire, a track switch located between said signals, a contact in said line wire closed only if said track switch assumes the main track position, and contacts closed only if said track switch assumes the main track position included in clearing circuits for said signals.

8. In a single track signaling system of the absolute-permissive-block type, in combination, with two signals for governing traic in opposite directions, a stick relay associated with each of said signals for when energized causing the next signal in the rear to indicate caution, a line wire extending from one of said signals to the other of said signals, a stick circuit for each of said stick relays including said line wire, a track switch located between said signals, a contact in said line wire closed only if said track switch as- ERNEST B. KEMPSTER, JR. 

